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Qualia

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  1. Qualia
    Measurement of Doubles and a Jovian Moon - Baader Micro Guide
    Introduction
    The reason for this rather long blog entry is to highlight what has been possible using simple and relatively inexpensive gear to measure the separation and position angle of a number of double stars and the sizes and distances of various objects within the Solar System.
    The preliminary goal was fivefold:
    to further skills in star-hopping and to gain a deeper understanding and appreciation of star magnitude.
    to garner some experience in measuring double stars as accurately as possible.
    to work out the sizes and distances of a number of night sky objects.
    to evaluate the capabilities of the 4” refractor.
    to pass on information that may be of interest or use to others.

    The Gear
    Mounted on an equatorial CG-5, I used a four-inch Tal 100rs f/10, a Celestron x2 Barlow and a Baader Micro Guide. This particular eyepiece is an Orthoscopic Abbe with a focal length of 12.5mm and equipped with a laser-etched reticle and screw on red-light variable illumination system.

    The multi-function astro-metric eyepiece provides sharp images across the field of view and has a twist up and down focuser which is not for eye-relief but to sharpen the finely etched designs for the observer. When focused at the centre, the edges of the scale do not blur and are crisp throughout but might be difficult to read on occasions due to the illumination system sometimes being uneven.
    There is no glare, stray light or internal reflection from the illuminator but on tighter doubles with a dimmer secondary component or on faint DSOs, for example, one finds they fade between subtle differences in reticle brightness. Lessening this brightness to capture the dimmer object sometimes makes it complicated to read the 360º protractor scale and I have found that the best remedy on such occasions is to dim in and out and use the eye’s memory to capture the reading.
    The sharply etched reticle scales include a 360° protractor at the edge of the field of view (4), a number of concentric guiding circles (3), a semicircle (2) and a linear scale across the centre (1).

    For general beginner’s use, the Micro Guide will be very useful to those who wish to work out seperations and angular distances of binary stars and sizes and distences of Solar phenomena, Lunar features, and other objects found within the Solar System and beyond.
    Focal Length
    In measuring a binary star’s separation in something as small as arcseconds, it is important to maximise that separation by using as much of the linear scale as possible. By using a barlow, one effectively increases the telescope’s focal length which in turn ensures not only a greater magnification but also a more accurate measurement along the 60 divisions etched onto the Micro Guide’s 6mm linear scale. This means that if separations or sizes are to be measured evermore accurately with only this eyepiece, different and greater focal lengths will eventually be required.
    Calibration
    Before being able to use the Micro Guide it is necessary to calibrate its linear scale, that is, to estimate the number of arcseconds in each division in accordance with the given telescope and if used, the given barlow. If ever the barlow or telescope is changed for another or not used, one must repeat calibration with the new set up. There are a number of ways of going about this and I include two methods, ignoring those given by the instruction manuel.
    The Split Method
    Find a known double star and note the number of divisions on the linear scale separating the primary from the secondary. If, for example, Albireo has a separation of 34.7” arcseconds and I see that this separation spans 4.6 divisions on the reticle’s scale, then I conclude that each division is 7.54” arcseconds in length.
    It is a good idea to measure the chosen double star 30º above the horizon to avoid overt atmospheric disturbance or refraction and to take a good number of measurements of that given star to find the mean average. For this method I chose similar partners in beauty but of various separations none of which were so tight that measurements would be rendered near guesses.

    Star Rho ( ρ) Counted Divisions Scale Constant Albireo 34.7" 4.8 7.23" Almach 9.7" 1.3 7.46" η Cas 12" 1.7 7.06" ζ Lyrae 43.7" 5.9 7.8" Summing and finding the average I now had a workable scale constant of 7.38" which would remain valid so long as I used the same gear.
    The Drift Method
    Again, the drift method is to determine the scale constant – the number of arcseconds per division - but I feel gives a more detailed approach and one less reliant of guessing. However, with that said the final scale constant was very similar to the Split method.
    Turn off any mount drives and time the passage a given star makes along the length of the linear scale from zero to sixty. The star doesn not have to be a double but will need a stopwatch counting to the 100th of a second. It's a good idea to find a star above 30º declination and not too near the Cestial Pole. You turn the eyepiece until the star drifts exactly along or parallel to the linear scale and as it crosses the zero line start timing until it crosses the sixtieth division. You repeat this process about 20 to 30 times in total over a number of days. To ensure as much accuracy as possible try to measure three different stars over a week and with the various timings for each star, calculate their mean average.
    The Drift’s Scale Constant
    You’ll then need to convert these particular results into arcseconds with the following formula:
    S.C. = 15.0411 (T.avg) cos (dec) / D
    S.C. – Scale Constant.
    15.0411 – Earth’s rotation rate per hour in degrees.
    T.avg – The given star’s mean average drift time.
    Cos (dec) – The cosine of the star’s declination
    / - Divided by
    D – The number of division on the linear scale
    And that’s it.
    The resulting figure will be your scale constant and will remain valid so long as the optical gear you use remains the same. In my own case, I found that the average scale constant was again around 7.5” arcseconds per division.
    Putting Numbers into Practice
    Over the following days, I tried to measure a number of double stars in the constellation of Perseus. In particular, doubles that I had never worked with. I chose Eta Persei, Struve 331 and Epsilon Persei as guinea pigs for the experiment. I took a number of measurements for each star and again estimated their average separation. The following highlights the concluding results where Est Rho is my estimation and Rho is the official separation.

    Star Est Rho ( ρ) Rho ( ρ) Error η Per 28.5" 28.3" 0.7% Σ 331 12.9" 12.3" 4.8% ε Per 8.1" 8.7" 7.4% As can be seen the margin of percentage error is significant and there is room for improvement. Nevertheless, the results were all within 1” arcsecond of error which accords with the kind of results expected from the Micro Guide. Baader informs the reader that “...such measurements can be estimated to an accuracy of about...2” for a focal length of 2000mm.”
    Working Out Position Angle
    I found that working out how to take a binary’s position angle quite complicated but eventually the following procedure was taken.

    The binary is centred in the eyepiece and aligned in such a manner that both components drift through the bisected middle linear division marked 30 on the Micro Guide. The two stars are allowed to drift toward the etched 180º semi-circle and as the primary crosses the inner 360º protractor scale one reads the given angle. It’s a good idea to take a number of measurements, but better still, place those stars dead centre for a general reading error of about 1º to 2º degrees.
    Measuring Sizes and Distances
    To measure size (S), count the number of divisions the given object takes up on the linear scale (sc). Divide this number by your set up’s focal length (fl) which will give you a general image-size (i). Multiply this with the known distance to that object (d).
    S = d (sc / fl)
    For example, to work out an estimate of the size of Ganymede, I found that it measured no more than about 0.01mm or 0.02mm on the linear scale: a mere dot on the etched reticle.

    The mean average of this number was divided by my set up’s focal length, giving me the estimated image-size. Noting that Jupiter was about 4.8 AU from Earth (718,069,776km) and that Ganymede has a average distance of about 1,605,000km from Jupiter, I calculated that Ganymede was around 716,464,776km from Earth. This number was multiplied by the image-size giving me a rough size of Ganymede at around 5,373km in diameter. An error of about 2% or around a 100km out.
    To calculate distance (d), you divide your focal length (fl) by the image-size (i) and multiply this by the known size (s) of the object.
    d = s (fl / i)
    Ganymede’s distance from Earth, I knew its size was about 5,373km (really its 5,268km) and was measured on the scale at about 0.015mm. You then divide the focal length by that image-size and multiply by the size of the object. In my case, I found Ganymede’s distance from Earth was about 716,400,000km. Again, an error margin of around 2%.
    Conclusion
    The Baader Micro Guide does not come cheap. In Europe it sells for around €165. In the boxed package you receive instructions (often vague), a decent 12.5mm Abbe Orthoscopic eyepiece with the built in finely etched reticle and a battery operated screw-on illuminator.
    Most will probably think that such an item is an unnecessary expense to include in their eyepiece collection but to counter this argument there is something rewarding in the challenge of meticuously recording and calculating distances and angles and sizes and separations – even if the experience can sometimes be frustrating and that these numbers have already be worked out for you.
    I have found the Micro Guide to be a useful resource for not only testing patience and recording skills, or the acuity of vision but also an aid in astronomical study.
    Like sketching or logging, the astro-metric eyepiece helps increase observing skills for it forces you to take note rather than just casually glancing. Indirectly, it helps increase knowledge about the objects you are looking at, for it is necessary to research such variables as size, distance, separations and position angles and by researching these variables and actively working with them, overtime you are gradually able to estimate such things in the field. Finally, it also acts as an impetus to structure a part of your observing session.
    After a good month with the eyepiece, working with the Sun and objects of the Solar System, I also feel I have come to appreciate a lot more such diverse factors as the quality of my optics and observing site, the effects of atmospheric seeing, sky glow, astronomical and mathematical data, patience, fatigue, mental disposition, and so on. Such insights will not only deepen your understanding of stargazing but also in coming to understand a little more about yourself – which afterall, must be one of the most important goals set out for us.
  2. Qualia
    Three Weeks in the Wilderness
    Between the 9th to the 22nd of August, I was fortunate to spend almost three weeks camping with my girlfriend in the natural park of Causses du Quercy, France. It is a beautiful area of hidden caves, prehistoric artwork, gorgeous villages, mellow rivers, cool breezes and summer sun, delicious wine, cheese and paté and some of the most precious skies in Europe.


    I was fortunate enough to take along my 10" Moonshane and head out with my girlfriend to an area known as The Black Triangle. Here, at night, the only light you see is that from the stars and from the Moon.
    Nature has given us two joys to accompany us through life: the playfulness and cheer of day and the solemn and silent night. In the first of these geniuses we visited the area; strolled rustic villages, dined on five course meals, had siestas by slow rivers and took trips into the underworld, a torch lit boat ride along underground rivers filled with ancient stalactites and stalacmites, another to visit prehistoric artwork and witness mankind's lasting steps into art and creation.
    At night, armed with pencils, blending stub and sketchbook I headed out into the darkness, into that night sky bent gently over my head revealing to me its infinity of tangled curls and wonder.
    Each night was a different voyage, some predominatly amongst doubles, others with NGCs, galaxies, nebulae and clusters. Many hours were spent just sitting back, ignoring the telescope and drinking in the slendour. It is impossible to include everything, sketching is an exhausting and concentrated effort and at best I could manage an average of about two a night. Although these sketches cannot do justice to nature's sublimity, I hope they give a hint of what was witnessed.
    Here, then, I include the sketches I made of just some of Messier objects viewed and a particular NGC.
    M 2

    M 8

    M 11

    M 13

    M 15

    M 16

    M 17

    M 20

    M 21

    M 22

    M 23

    M 24

    M 26

    M 27

    M 28

    M 31, M 32, M 110

    M 33

    M 34

    M 45

    M 52

    M 57

    M 72

    M 73

    M 74

    M 75

    M 76

    M 81, M 82

    M 92

    M 101

    NGC 6960

  3. Qualia
    M 35 and a Mystery
    M 35 presents a gorgeous field of stars and must rank as one of the most beautiful open clusters in the heavens. Typically you see gentle curves and woven strands of frosted silver stars terminating with a larger, brighter and more colourful one at the curve’s end.
    Sketch of M 35
    It comes as little surprise, then, that observers have likened its pattern to an exploding rocket or bursting firework consisting of several hundred stars scattered over an area covered by the full Moon.
    For us, M 35 or NGC 2168 lies at the base of the constellation of Gemini and probably itself in the plane of the Milky Way some 2,800 light years away and 24 light years in breadth and if it were not for swarths of interstellar dust lying in the line sight it would truely be a naked eye object.
    Location of M 35
    Although bound together by its own gravity, the relatively young cluster of about 100 million years old is gradually breaking up as a result of random encounters among stars that speed its members to escape velocity. Most of the stars we do find here are more massive than the sun itself and burning at extremely high temperatures, which makes them blue-white in color. The red stars in the cluster are nearing the ends of their lives and have swelled into red giants.
    In the 4” telescope, I could easily make out about 40 to 50 stars, bright blue, silver and white blazing in the field of view, along with a few red giants evolving off the main sequence. Somewhat more to the south-west from M35, I came across what seemed like another open cluster. It contained fewer stars and was a lot looser than M 35 but it curved with a similar grace and appeared to contain a number of very hot young OB stars. I’m not sure if this area was still part of M 35, or perhaps the open cluster IC 2157.
    The Mystery Cluster
    Whatever the star field was both presented an archingly beautiful sight and one worth seeking out time and time again.
    The sketches were made using a Tal 100rs, 25mm X-Cel LX, a black pen for the brightest stars and a 4B and 2B for the lesser magnitude stars plotted on white paper.
  4. Qualia
    The Eskimo Nebula - A View from the Arid Lands
    By Way of Introduction
    In a manner of speaking, we are born out of the earth, walk on it for a while and finally become part of it when we die and so too with a star. It is born out of the cosmos, wanders it for a while and finally becomes a part of it when it dies. In this way, both a star's existence, like a human life, is a rite of death, a being-towards a something else; a transformation.

    The physical recycling of life serves as a reminder of our own ultimate fate and likewise that of the Sun; for the star that was once the Eskimo Nebula is a good illustration of what the Sun’s own passing away will be like as it ejects its matter into space, forming giant gas and dust clouds which may condense with other interstellar material into planets and stars, comets and meteorites and organic life.

    The Eskimo Nebula or NGC 2392
    The Eskimo Nebula or NGC 2392 was a sun much like our own, a typical main sequence star chugging along in a steady state of nuclear fusion, transforming 700 million tons of hydrogen into helium every second for billions of years. Then about 10,000 years ago - as the ice-age was coming to an end - the hydrogen supply in the star’s core ran out. Nuclear fusion ground to a halt and through the force of gravity, the helium core collapsed creating temperatures high enough to trigger the fusion of helium into carbon and oxygen.
    Far from the burning core, on the outer hydrogen layers, the star was expanding into a red giant, a colossal stellar object with a diameter of at least 2 AU. Once the helium fusion ended, the core collapsed again, but now there was not enough energy to spark further nuclear reactions or to counter the force of gravity and so the star collapsed until it was about the size of Earth and became a white dwarf.

    The Eskimo’s white dwarf is a relatively small object in terms of volume but it packs a lot of mass. It is probably about the size of Earth but with a mass equal to that of the Sun. Surrounding this stellar remnant is a shell composed of expanding helium and hydrogen gases whose electrons are excited by ultraviolet radiation emitting from the white dwarf in the form of stellar winds.
    The excited gas is visible as a planetary nebula, detected in a small telescope as a bright, ghostly cloud whilst with deep exposure you can witness one of the most captivating and intrinsically beautiful objects found in the natural world.

    Not only is the Eskimo Nebula aesthetically gorgeous but as with all things which must come to pass and die, it too contains the building blocks of life. Spectroscopy has detected four primary elements within it, namely, hydrogen (green), helium (violet), nitrogen (red), and oxygen (blue). Indeed, the nebula’s name derives from these gases which light up as a ‘hood’ surrounding a ‘face’ made up of two elliptical lobes. No doubt, the snub that is the nose is the small central star.
    The Eskimo Nebula is estimated to be anything from 2,870 to 5,000 light years from Earth, has a diameter of about half a light year and the gas we see probably left the small central white dwarf some 1,500 years ago. If this is so, NGC 2392 is one of the youngest planetary nebula known.
    A Sketch & Observation
    The planteary nebula lies in the constellation of Gemini and even with the small 4” refractor, it was clearly visible and held up well to magnification. As can be seen from the sketch, there was a brighter central region surrounded by a fainter halo of nebulosity and although the inner circle hinted at more detail, due to average seeing conditions and probably being at the refractor’s Dawes limit, the tiny white dwarf at approximately magnitude 10.5 was not seen.

    However, this was not important. That bitter evening this sketch was made the Eskimo Nebula shone forth as a comforting metaphor. The original sun - which had been so much like our own - was now long gone but it did not sleep, it had not died. It was just something else.
    Equipment used for the observation was a Tal 100rs, an 18mm X-Cel LX mounted on an AZ 4. The sketch was drawn the 12th of November, a cold night using a 4B, 2B and B pencil for the stars and a blending stub for the nebula.
  5. Qualia
    Messier 15 - A View from the Arid Lands
    Imagine a world where the sky blazes with the radiance of a hundred thousand suns. That in any direction you ever cared to look you saw more stars crowded together than anywhere else in the Milky Way – anywhere, perhaps, than that of our own galaxy's hidden heart.
    Imagine a world of midnight brightness, a world without shadow, where the love of warmth would burn everything to ash. This would be the world of Messier 15, a primordial remnant forming from the birth of the Milky Way. The densest known star cluster in our galaxy, cranking out a vast array of exotic stellar objects from pulsars, variables, binaries, red giants, white dwarfs and neutron stars, planetary nebula, supernova and maybe even a black hole.
    Messier 15 Sketch
    As the story continues, Messier 15 is about 12-billion-years old, some 33,600 light years away and hurtling towards Earth at around 385,000 km an hour. It has a diameter of about 175 light years and an absolute magnitude of roughly 360,000 times that of our sun.
    The cluster has been identified with an overall spectral type of F – typically characterized by weak hydrogen but strong metal emissions - suggesting that the vast majority of its stars have evolved away from main sequence and – depending on their mass – will one day explode into supernovae or collapse into planetary nebulae, leaving the remnant of neutron or white dwarf stars respectively.
    Images from the Hubble Telescope show that Messier 15’s super dense core has undergone a process of core-collapse driven by the intense gravitational pull of thousands of stars converging on a small volume of space rather like cosmic bees swarming to their hive. Photos of the 22 light year diameter core, reveal a world of over 30,000 distinct stars and it is still unknown whether this core is packed to such an extent by mutual gravitational interaction of the stars or whether it now houses an object resembling that of our galaxy’s nucleus.
    At this core, neutron stars and white dwarfs outnumber main-sequence and red giant stars by a ratio of about 100 to 1 and theories suggest that either the core has stopped collapsing and stars near the center have settled into uneasy cosmic dances, both attracted to each other by gravity and repelled by close encounters that slingshot them through space, or that at some stage in M 15’s ancient history there has already occurred a massive pileup of stars forming a black hole several thousand times more massive than that of our sun.
    Artist's impression of Black Hole at the heart of a Globular Cluster
    Some 150 light years away from the intense brilliance of its central core, towards the cluster’s halo, the Milky Way’s own tidal forces and tidal shocks are stripping away and destroying any low-mass stars remaining. Messier 15 is an unforgiving world and it is probable that its current star population is a mere fraction of what it once was.
    At the very limit of naked eye visibility with its apparent visual brightness of magnitude 6.2, as shown in the sketch above, M 15 appeared as a small, rounded and mottled nebula in the 4” refractor, with at best subtle indication of some of its brightest stars or star-areas. The compact core remained unresolved but with attentive inspection hints of star streams could be seen radiating out from its core in all but its most westerly direction.
    Equipment used for the observation was a Tal 100rs, an 18mm X-Cel LX mounted on an AZ 4. The sketch was drawn the first weekend of November, a cold night using a 2B pencil for the stars and a blending stub for the globular cluster.
  6. Qualia
    The Double Cluster - Caldwell 14
    The Double Cluster or Caldwell 14 in Perseus is a visual extravaganza and probably one of the most breath-taking sights to be seen in the night sky. On a good night the soft glow from the combined light of the two individual clusters resolve into an awe-inspiring swarm of literally dozens upon dozens of blue and white stars surrounded by just as many unrelated Milky Way stars.

    The true brilliance of the Double’s stars are dimmed by swaths of heavy galactic dust clouds between ourselves and the two clusters which render their members over four times fainter than they really are. In these terms, it has been estimated that if the Double were located at a similar distance of the Pleiades (some 407 light years away), about one quarter of our northern sky would be filled by its stars and hundreds of its members would shine more brilliantly than the planet Venus.
    NGC 884 and NGC 869 are located at distances of some 7,600 and 6,800 light-years from Earth respectively and thus are physically close to one another in space. Both clusters are found in the Perseus Arm of the Milky Way - we ourselves are riding the Orion Arm – and are about 5.6 million years and 3.2 million years old respectively. If we consider that an open cluster like that of Pleiades is thought of as a young cluster with about a 100 million years of age, then clearly the Double is a mere infant in cosmic terms.

    The Double’s stars formed at approximately the same time and from the same primordial molecular cloud of dust and gas. Spectroscopy has revealed that many of the stars have a very high concentration of heavy elements and typically are super hot and very luminous O and B types. These massive stars are aging very quickly and few will live to a billion years; instead they will eventually self destruct into supernova, creating shock waves powerful enough to disrupt the already two loosely bound open clusters and disperse their stars. In consequence, the Double will probably be unrecognizable as a cluster within 250 million years or so.
    The sketch itself was a tad complicated to complete and no doubt is not entirely accurate. These two clusters are quite complex to sketch due not only to the sheer amount of visible stars seen and the sense of differing stellar magnitude but also in the beautiful variation of colour observed at the eyepiece.

    The best plan of approach was to draw up a target-clock-face with 45º angles and concentric circles and use this as a template. To achieve some sense of variation in star magnitude I used an ink-pen for the brighter stars and various grades of pencils for the dimmer stars ranging from 4B to B. Over the sketch was taped a piece of tracing paper to which I noted the more prominent star colours on the overlay. To capture the best possible field of view with the 4” f10, I used the lowest magnification I have in my collection, namely, a Celestron LX 25mm.
  7. Qualia
    Double in Perseus - Part II
    Epsilon Persei (ε Persei)
    Struve 471
    RA / DEC: 03:57:9 / + 40.01
    Magnitude A / B: 2.8 / 8.8
    Rho: 8.7”
    Theta: 10º
    Epsilon Persei is huge. It is young and burning at an extremely high temperature – around 27,000k – giving it that distinctive blue-white hue so common amongst the stars in Perseus. It has a luminosity of about 28,000 Suns, is around 16 times the Sun’s mass and nearly four times bigger. Needless to say, like so many other stars in Perseus, with less than 10 million years of age, Struve 471 in a few million years time is destined to explode into a magnificent supernova.
    Around 538 light years from Earth by all accounts Epsilon Persei is a spectroscopic binary meaning that the only evidence of a binary star comes from the Doppler effect on its emitted light. It is also one of the most commonly known exteme variables in the Milky Way which means the absorbtion lines seen on the spectrum are varying rapidly in the space of just few hours.
    Nevertheless, for the observer, a small, fainter dwarf companion can be seen with a separation of about 10” of arc, implying that this secondary is at least 1,600 AU from the primary. It is very unlikely that this is a true companion making Struve 471 a line of sight double.

    At around 50x the secondary was barely visible but upping the magnification to around 140x greatly improved matters and it was easy to split the very bright primary from the fainter bluish companion.
    40 Persei
    Struve 431
    RA / DEC: 03:42:4 / +33.58
    Magnitude A / B: 4.9 / 10
    Rho: 19.8”
    Theta: 244º
    As should be obvious by now, the constellation of Perseus is noted for containing a lot of class B stars probably of which are part of the OB Association. These stars are massive and dying young and many will explode into supernova. In the not too distant cosmic future, the constellation of Perseus will be a new breeding ground for Solar Systems and planets and will probably be as aesthetically beautiful as is M 43 in Orion.
    40 Persei or Struve 431 is no different. It is another class B star dimmed only by the huge quantity of interstellar debris and dust between it and Earth. With a surface temperature of around 28,700k and a luminosity of about 23,600 suns, when its hydrogen fusing lifetime is over and its helium core is complete, it will probably become a Super Red Giant, leading to its total collapse and massive explosion as a supernova.
    Between 924 to 1055 light years away, 40 Persei is listed as having two companions. A 10th magnitude optical coincidence 20” of arc away from the primary and a spectroscopically detected neighbour.

    At the eyepiece, the optical double was easily split revealing a bright bluish star and a fainter blue companion.
    Struve 446
    RA / DEC: 03:49:5 / + 52.39
    Magnitude A / B: 6.8 / 9.9
    Rho: 8.9”
    Theta: 254º
    Jeweled within the small and sparsely populated cluster of NGC 1444 is Struve 446. Another B type star and probably not part of the cluster which is some 3,330 light years away. Information on this little gem was scant, but as can be seen from the sketch, it really is a very pretty double with the light, golden-yellow primary, and a fainter blue companion easily split at around 100x to 140x. Well worth seeking out.

    Struve 268
    RA / DEC: 02:29:4 / + 55.32
    Magnitude A / B: 6.7 / 8.5
    Rho: 2.7”
    Theta: 131º
    Struve 270
    RA / DEC: 02:30:8 / +55.33
    Magnitude A / B: 7 / 9.6
    Rho: 21.4”
    Theta: 305º
    Struve 268 is another main-sequence B star about 649 light years away whilst Struve 270 is between 166 to 181 light years away and burning with a mass of about 4 suns. It has been observed that Struve 270 is emitting strong infra-red emissions suggestive of a recent catastrophic collision between itself and some planet or planetary embryo.
    What makes Struve 268 and Struve 270 so striking is the fact that they’re both woven into a beautiful, open field of frosted silver, bright blue and white stars. Although Struve 268 was relatively easy to split at around 140x, I preferred to sketch the entire star field which would also include Struve 270 at around 50x. In consequence, Struve 268’s companion appears and is a very tight split at this magnification whereas Struve 270 remains an easy, wide double.

    Struve 268 was seen as a relatively bright bluish star with a fainter white companion whilst Struve 270 had a notable yellowish hue to it and its companion was a fainter blue. There is a C and D component for Struve 270 but at around 12th magnitude I had no luck in spotting them and figured either my telescope wasn’t up for the job or the city’s sky-glow had simply drowned them out.
  8. Qualia
    Some Doubles in Perseus - Part I
    Eta Persei (η Persei)
    Struve 307
    RA / DEC: 02:50:42 / +55.53
    Magnitude A / B: 3.8 / 8.5
    Rho: 28.5”
    Theta: 301º
    Eta Persei, Struve 307 or Miram, lies at the northern most tip of the constellation of Perseus about 1,331 light years away. Classed as a K3 supergiant, the star is estimated to be about 11 times the mass of the sun with a diameter 105 times greater and radiating with a luminosity of about 35,000 suns. The future of the star is still unknown but it is reckoned that if it its helium has already been exhausted, then it will probably become a huge white dwarf and if it is still expanding it may explode as a supernova.
    Struve 307 appears to have six or so companions, but this is probably more a line of sight coincidence rather than being all genuine secondary components. More than likely, Eta Persei has a true B and C component consisting of two B Dwarf stars.

    Struve 307 is easily split at around 50x and with the ease of such magnification the contrast between the orangey supergiant and its lighter blue B companion is perfect making this a pretty and serene double to observe.
    Upping the magnification to around 140x brings forth those fainter components which act as an attractive frame to the main star and it is possible to pick out not only the B companion but also Eta Persei’s C and F components. I found that with my limiting aperture averted gaze gave the best results to tweak out these fainter 10 or 11 magnitude stars. Considering I only expected to find a binary pair and ended up with a crowd made this a rather winning double.
    Struve 331
    RA / DEC: 03:00:9 / 52.21
    A / B: 5.21 / 6.17
    Rho (ρ): 11.9”
    Theta (θ): 85º
    The colour and aesthetic appeal of Struve 331 is as diverse as it is a mystery. Some observers claim that they see in the binary pair light shades of blue, others gentle tones of yellow, some just see a plain white pair, others a dusty blue green and hues of golden orange. Aesthetically speaking, observers have claimed anything from seeing a boring and dull binary to a spectacular showpiece. It seems, then, that the double is a bit of a cosmic chameleon and no doubt conditoned itself by the mood, disposition and quality of seeing of each individual stargazer.
    Struve 331 is probably an optical binary lying some 800 light years away. Its two components are considered to be main sequence B dwarf stars which typically have a mass 2 to 16 times that of the sun and because they are burning hydrogen at such a fast rate have a surface temperture of anything between 10,000 to 30,000 k. For this reason, B-type stars are often extremely luminous and blue.

    The component was easily split at 50x but gave better results around 100x. Some fainter stars can be gleaned from the dark surroundings but there is nothing here which stands out as an interesting asterism. In this fashion, coming across Struve 331 was a bit like spying two distant and frosted headlights approaching from some dark and misty wilderness.
    Zeta Persei
    Struve 464
    RA / DEC: 03:54:1 / 31.53
    A / B: 2.86 / 9.16
    Rho (ρ): 12.9”
    Theta (θ): 207º
    Classified as a B1 supergiant, Eta Persei or Struve 464 is estimated to lie somewhere between 750 to 1,300 light years away, burning with a luminosity of anything between 47,000 to 105,000 Suns. Its sphere is around 13 to 20 times the diametre of the Sun and between 13 to 19 times its mass. Clearly, Zeta Persei is enormous.
    If all the interstellar dust and gas and other cosmic debris could be removed between the star and ourselves, Zeta Persei would shine like a first magnitude star. It is probably part of the OB Associations – groupings of hot, massive and relatively short lived O or B classed blue stars which are not gravitationally bound but slowly disintegrating as the individual stars move their separate ways. At only 9 million years old, Struve 464 is a mere child-star when we consider that most stars do not begin to significantly age until they are between 1 billion to 10 billion years old and yet its fate is already sealed; the star is dying and will one day explode as a supernova.
    Struve 464 appears to have four companions, two being true components (B & E) and two line of sight coincidences (C & D). The 9th magnitude B component is also a B star but is more than likely a subgiant. It orbits the A component with a distance of about 3,900 AU and takes about 50,000 years to make a full circuit. The E component is also a magnitude 9 star but probably a stellar type A about 36,000 AU away from the primary and orbiting it over a period of some 1.5 million years.

    As can be seen in the sketch, Zeta Persei was sighted as bright bluish giant whilst the B companion was barely visible beyond the primary’s glare and at best with the practice of averted vision came across as a mere dot. At pretty much exactly the same position angle but farther out the D and E components were faint but clearly visible. The C companion was lost in the shining of Zeta Persei. A low 50x magnification gives the eyepiece view a more aesthetic appeal but I needed to up the magnification to over 100x to tweak out that B component.
    Struve 292
    RA / DEC: 02:42:5 / 40:16
    A / B: 7.56 / 8.23
    Rho (ρ): 22.7”
    Theta (θ): 212º
    There’s really not a lot of information to be found on Struve 292 and this is a shame, for one could start to believe that some of the best doubles to observe are forgotten simply because their contrast of colour or the challenge of their split doesn’t give one that immediate satisfaction. Struve 292 is probably a huge B type star about 1,000 to 1,500 light years away and with a mass of anything between 2 to 16 times that of the Sun. It may not be one of the most beautiful doubles in the night sky but as can be seen from the sketch it is a rather attractive and easily split binary set within an astonishing spectacle of other sparklers near M 34.

  9. Qualia
    NGC 752 - A View from the City
    NGC 752 or Caldwell 28 lies well within Andromeda's borders, just a few degrees southwest of the spectacular double star, Gamma Andromeadea.
    Amidst the splendor and easy attraction of Andromeda’s galaxies, NGC 752 is an often overlooked but beautiful open cluster and will no doubt be a pleasure to contemplate through binoculars or a low-magnification eyepiece.
    What I saw at 40x in the f/10 overfilled my field of view; four dozen and more sparkling gems scattered across space with a star magnitude ranging from the very bright at about 8 magnitude to the barely visible. The cluster not only overfills the field of view but also the imagination; the place where stargazing really takes off. It’s about 1,300 light years away with an age of over 2,000 million years old (English speakers may prefer to say, 2 billion years old), which makes it one of the oldest visible open clusters in the Milky Way.
    This cosmic age is clearly visible in the subtle colouring of the cluster’s stars. Relatively young clusters such as Pleiades, which is probably no more than a 100 million years old, consists of mostly young, bright and beautiful blue-white stars, whereas in NGC 752, you can clearly see that many have evolved into main sequence red-giants.
    Over a few nights with the aid of the Micro Guide eyepiece, I tried to estimate the size of just one of the little red gems (the middle star of the triangle at the bottom left of the sketch at about 7 o'clock) and noted that it appeared to measure somewhere between 600 to 800 million kilometers in diameter, clearly equalling the enormity and splendor of Antares or Betelgeuse.
    It is not only the colour of the stars that give away NGC 752’s age. It is also shown in the way the cluster is so spread-out. As it circles the Milky Way, the gravitation of other huge objects like stars and massive dust clouds tug and pull at the cluster, gradually wearing away and weakening its own mutual attraction. No doubt a few billion years ago, NGC 752 was as spectacular as any of Messier’s popular globular clusters; today it remains a relative secret.
    The sketch itself was drawn in the city with a black pen on white paper at 40 magnification. Back at home, I tidied the sketch and added colour which had been coded on site.
    The Tal 100rs, a 25mm X-Cel LX EP, the CG-5 and a pirate's eye patch were used as tools of trade. Compromised by my field of view, the given sketch hardly does the cluster justice but I had to choose what I considered the best point of view and get on with it.

  10. Qualia
    Some Doubles in Andromeda
    Perhaps there are some who think doubles are merely two stars close together and they may be right, just as one may be right in saying great music is only a bundle of notes strung together or that literature is just a large collection of words. But as with most things in life, if you spend time with doubles, hunting them out and learning from them, you come to realise that the grand majority radiate an aesthetic beauty quite unlike anything else.
    As with any art, there need not be any purpose in splitting stars, just as there need not be any necessary purpose in strolling through a forest at dawn, viewing a beautiful sunset or writing a poem to your loved one, but we can also highlight some of the more utilitarian reasons for undertaking such a pursuit:
    star systems are among the very few objects in the night sky to show you any real colour, in some cases majestically bright and vibrant. This gives the pursuit a rather pleasing aesthetic appeal.

    tracking down doubles gives you excellent practice in the art of star hopping and in reading and using star maps and charts.

    seeing conditions will often influence your success, so by observing doubles on different nights you can gain familiarity with how how appear in your telescope under varying conditions.

    like lunar and planetary observing, you can observe doubles from your own garden or roof top under quite heavy LP, so you don’t need to be hanging around for perfectly dark nights or sites.

    searching for double stars teaches you something about your telescope’s resolving power, its ability to provide you sharp and detailed viewing, even of objects that upon initial appearance come across as a single source of light.

    by comparing the double and multiple star systems you can practice your understanding and skills at recognizing differing star magnitudes.

    Andromeda is a fascinating constellation in itself with many beautiful objects to discover. The following are a few sketches of some of the wonderful double stars it conceals.
    I hope you enjoy them and I will see you all after a little holiday break. Should be back at the end of the month.
    Bye for now.
  11. Qualia
    Lunar Observations and Sketches
    This week, I've decided to wake up early and view Jupiter. This has been far from an easy task, but surprisingly, seeing has been rather good at these early hours of the morning and Jupiter’s two great bands and Giant Red Spot were easily visible every observing session.
    I drew an image of what I saw at around 4am, returned to Jupiter about an hour later to draw another field sketch and then wound the practice down as the sun rose around 6am.
    With these sketches in hand, I divided the total angular movement perceived into 15 minute frame shots. Often, between these smaller sketch-shots, there was very little observable movement, so I cheated a little and used Sky and Telescope's program to help me find some of the slower moons’ orbital movement and direction. Nevertheless, with that said, what you see is very much what was perceived in the entirety of the observing session between the two hours.
    I have tried to sketch Jupiter as accurately as possible but was compromised between either drawing it to seeing scale or colouring it to what was seen. With the free program I use (Piant.net), it wasn’t possible to do both, so in the end, I opted for accuracy in size. Jupiter, as seen from the eyepiece, should have its bands just a little darker, with a more rusty feel to them and with more observable lines seen within both its belts and zones.
    I have placed the sketches from the most recent session to those conducted the previous week. Of particular interest has been those drawn today, 30th July, which show Io’s shadow cast over Jupiter’s surface. If you open up the sketches and save them, you will be able to flick through each seeing session quickly and by doing so, like an old fashion film, you will be able to perceive the four Galilean moons’ general orbital movement.
  12. Qualia
    Epsilon (ε) Lyrae & Struve (Σ) 2470 & 2474
    Epsilon (ε) Lyrae, HIP 91919 - The Double Double
    Along with Albireo in Cynus, the Double Double in Lyra is probably one of the most viewed multiple star systems in amateur astronomy; it is relatively easy to find, makes a good test for one's optics and scope and is rather beautiful to behold. It is estimated that the star system is some 162 light years away from Earth, separated by billions of miles and orbiting each other over a period of hundreds of thousands of years.
    ε1 (to the right in the sketch) and ε2 (to the left) can be split themselves into two further binary star systems which again are orbiting each other. The component stars of ε1 have magnitudes of about 4.5 and 6, and ε2 about 5 and 5.5 and again are separated by billions of miles, each orbiting their partner over a period between 1,200 and 600 years respectively.
    The two binary pairs are probably Type A, dwarf stars, something similar to Sirius, Deneb or Vega, with a mass of about 1.5 to 2 times that of the Sun. Typically, dwarf stars are young stars with just a few hundred million years of age. It is understood that there are also a number of other stars which could be part of the Epsilon star system. ε2, for example, might have another star orbiting its binary pair and collectively, ε1 and ε2 could have a total of ten other stars held by the same gravitational pull.
    A City Observation
    Although Epsilon Lyrae is easy to find and split into the two distinct components, splitting these again is very difficult. As can be seen from the sketch below with the 4” at about 140x, a clean separation wasn’t possible.
    Perhaps I will need to re-observe and re-draw the Double Double over the winter months when seeing conditions in the city are better, but, perhaps, this isn’t the real answer. I feel that resolving this particular double doesn’t only depend upon atmospheric steadiness and dark skies, but also on my own vision which these days may not be up to scratch.
    Struve (Σ) 2470 & 2474 – The Other Double Double
    Σ 2470, the more northern one to the right, appears to consist of a bluish-white primary and a fainter blue companion at about 6 and 8 magnitude whilst Σ 2474, again at about a 6 and 8 magnitude, appears to consist of a reddish-yellow primary with a fainter, lighter yellow companion. Σ 2474 is said to be another binary star system in itself, whilst a 11 magnitude orbital partner, known as the C component, can be seen just left of it at about 120º.
    Σ 2474, like the sun, is believed to be a Type G star about 160 light years away. Σ 2470, on the other hand, is thought to be a Type B star with about 16 times the mass of the sun and over 1,300 light years away. It follows that collectively, this ‘Other Double Double’ in Lyra, although a stunning visual binary, are not physically related and so are not true double binary systems.
    A City Observation
    Although not nearly as well know as their Epsilon partners, aesthetically speaking I find Struve Σ 2470 and Σ 2474 far more appealing. The double is an easy, low power split, lying parallel rather than perpendicular to each other and being less a magnifying challenge than Epsilon Lyrae, the double appears somewhat brighter whilst offering the observer a richer field of stars as a gorgeous backdrop to the colourful binary system.
  13. Qualia
    NGC 7510 - Open Cluster
    NGC 7510 is a young, open cluster in Cepheus just a couple of degrees below M 52. It is estimated to contain anything between 30 to 60 member stars, scattered across 10 to 15 light years of space and ranging from a magnitude of about 8 to 15. It is about 107 years old and although relatively unknown, its distance from Earth has been valued from anything between 7,000 to just under 17,000 light years. Putting this into some perspective, as the cluster's light reaches you, it began its lonely voyage while the Neolithic era was still in full swing, rice has probably just been domesticated and the wheel is more than likely still a promise for the future to discover.
    NGC 7510 is a gorgeous cluster and to some extent resembles an arrow's head. The whole area is faintly tinted with a huge nebulous haze, a great cloud of ionized hydrogen subtly concealing a background of fainter stars trying to emerge from the quiet and solitary darkness and carve out their own brilliance in the night sky.
  14. Qualia
    M 39
    M 39 is a rather unassuming open cluster about 101 thousand lights years away and estimated to be about 9 light years across. The vast majority of brighter stars are Type A, Dwarf stars, something similar to Sirius, in their main sequence stage (burning hydrogen at their cores), whilst the brightest star is a Type B with a magnitude of about 6. This understanding has lead to an age estimate for M 39 of about 240 to 280 million years; a long time, but as things go in the universe, M 39 is almost a baby, especially if you start comparing it with globular clustsers.
    M 39 is one of the closest and smallest Messier clusters which helps explain its rather loose and angular visual appearance and even in a small aperture viewfinder, it is obvious that it is composed of stars, making it a wonder why Messier placed M 39 in his list of pseudo-comets in 1764. Other astronomers have been equally less-impressed. Herschel noted that it was 'coarsely scattered', Rosse of 'little concentration' and Smyth observed that it was a 'little splashy'.
    City Observations
    It is said that M 39 can be seen with the naked eye from a sufficiently dark site, appearing as a brighter spot within the rich star field of the Milky Way but in the city it is invisible and with no clear, nearby stars to guide you, it can be quite a challenge to find. Nevertheless, contrary to Herschel et al, I think it is well worth the effort.
    In the viewfinder, M 39 looks like a triangle filled-in and surrounded by a relatively rich field of sparklers, making it a perfect observation for owners of low f/ratio scopes or low magnification eyepieces of about 32mm. I have no idea what stars should be included in the cluster, nor, let it be said, whether the sketch I have included is M 39 or one of the other rich clusters found in and around Cygnus. I have read that about 20% of the stars brighter than 10th magnitude do not even belong to the cluster, so probably what I have included in the sketch will be a tad misleading. If anyone could guide me here, I would be most grateful.
    A useful tip for this given cluster is to sit with her for a while and let the different star colours become evermore apparent. I have tried to include the differing colours seen, but obviously this will be quite a subjective experience.
  15. Qualia

    Part III - Space

    By Qualia,

    Here I will conclude this little three part series. You can find the other two parts here:
    Part I: http://stargazerslou...3-part-i-space/
    Part II: http://stargazerslou...-part-ii-space/
    Up to this point, every wave known to science travelled relative to some medium, so where was the substance for light? Experiments were failing to find the Aether and Maxwell’s own equations did not conjure up such a substance, so what was going on?
    It was simple, argued a young Einstein, light, unlike any other wave does not need a medium. Light's speed is relative to anything and everything. It doesn’t matter if you are travelling towards or away from light, for it will always be measured at a constant speed of 671 million mph.
    The upshot
    So what exactly is being said if we conclude that the speed of light is a constant?
    As we have seen:
    velocity is a measure of space (distance travelled) divided by a measure of time (duration of journey) and,
    space and time were generally considered absolute.

    With these two premises in place, it was concluded that any measurement between two spatially separated objects, any measurement in space, would always be absolute. It didn’t matter if you, I or some cosmic entity did the measuring, because, in principle, we should all agree on the measurements taken.
    And exactly the same argument followed for time. It didn’t matter who measured how much time it took for something to happen, because, once again, in principle, all would agree on the measurements taken.
    But according to Einstein, the old generations assumed too much with that second premise. People moving relative to each other will not find identical values for time and space and this follows from the premise: the speed of light is a constant.
    Accordingly, if you chase light at 670 million mph, I will measure the light racing away from you at 1 million mph and you will measure the light running away from you at 671 million mph. The speed of light in either case has remained constant, yet space and time are rendered completely relative just as Kant had informed us more than a hundred years earlier. Namely, that each of us carries our own measuring rods of space and time.
    Special Relativity
    Before Einstein, it was generally believed that time and space were two very distinct entities, but, for argument’s sake, Einstein found them to be two sides of the same coin.
    Imagine you’re driving your car in a straight line and all your car motion is going into that straight line. Imagine now that you take a curve up ahead and you do nothing to compensate for the curve, then some of your original straight line velocity will go into that curve, leaving you a little less for the straight line.
    By analogy, if time and space are different sides to the same coin, then we can imagine a parked car which isn’t moving through space and so this means all of its motion is going through time. But if that car suddenly speeds away, some of its time motion will now be directed into space motion, meaning that there’s a little less motion for time, so it will literally slow down for the car.
    In other words, just as some of the car’s straight line velocity was directed into the curve in the first example, in the second example, some of the car’s space motion is diverted into time motion.
    And it is this very curious feature that Special Relativity is arguing; namely, that the combined velocity of any object through space and time is always equal to that of the speed of light. Thus, motion is a combination of motion through space and time and these two motions are absolutely complementary.
    It follows that the faster you move through space, the slower time will pass and to give some idea of this ratio, for every three hours we pass at rest, two hours will pass at about 500 million mph and at the speed of light, when all your motion is directed into space motion, time should, in principle, stop.
    The light from the stars and the planets you gaze upon at night have never aged when their pretty coloured photons hit your enquiring eye.
    And this is one reason why it is considered that nothing can go faster than the speed of light. It is simply because there is no more time motion to draw upon, its all used up. Travelling at such a speed leaves no more time for time.
    And that, for now, is the end of our little wander into space. I hope you enjoyed the read.
    You can find the other two parts here:
    Part I: http://stargazerslou...3-part-i-space/
    Part II: http://stargazerslou...-part-ii-space/
  16. Qualia
    General Plan
    I've decided to include my general observing plan for the warm summer months ahead because I feel it will not only help direct my own observations and studies but may also help other folk trying to decide what urban wonders they might be able to try for in the following weeks.
    The listing information includes Messier objects, NGC wonders, and Double Star gems which I think are worth taking a shot at even if the possibility of success isn't 100%.
    Unless directed otherwise the listing will be set out as follows:
    Target Name: Constellation; Type; Level of Subjective Difficulty 1 (relatively easy) to 4 (very difficult).

    The Messier List

    M 13: Hercules Globular Cluster 1
    M 92: Hercules Globular Cluster 2 - 3
    M 29: Cygnus Open Cluster 2
    M 39: Cygnus Open Cluster 3 - 4
    M 5: Serpens Globular Cluster 2
    M 16: Serpens Open Cluster 1
    M 10: Ophiuchus Globular Cluster 2
    M 12: Ophiuchus Globular Cluster 2
    M 19: Ophiuchus Globular Cluster 2
    M 62: Ophiuchus Globular Cluster 2 - 3
    M 107: Ophiuchus Globular Cluster 2 - 3
    M 57: Lyra Planetary Nebula 1
    M 56: Lyra Globular Cluster 3 - 4
    M 27: Vulpecula Planetary Nebula 2 - 3
    M 71: Sagitta Globular Cluster 4
    M 8: Sagittarius Galactic Nebula 1
    M 17: Sagittarius Galactic Nebula 1
    M 20: Sagittarius Galactic Nebula 3
    M 21: Sagittarius Open Cluster 3
    M 23: Sagittarius Open Cluster 2 - 3
    M 22: Sagittarius Globular Cluster 3 - 4
    M 25: Sagittarius Open Cluster 2 - 3
    M 28: Sagittarius Globular Cluster 3 - 4
    M 54: Sagittarius Globular Cluster 4
    M 55: Sagittarius Globular Cluster 3 - 4
    M 11: Scutum Open Cluster 1
    M 4: Scorpius Globular Cluster 2
    M 80: Scorpius Globular Cluster 3
    M 6: Scorpius Open Cluster 1 - 2
    M 7: Scorpius Open Cluster 1 - 2A Few New General Catalogue (NGC) Wonders
    NGC 6235: Orphiuchus Globular Cluster 4
    NGC 6572: Orphiuchus Planetary Nebula 2 - 3
    NGC 6910: Cygnus Open Cluster 2
    NGC 6866: Cygnus Open Cluster 3 - 4
    NGC 6819 Cygnus Open Cluster 2 - 3
    NGC 6826 Cygnus Planetary Nebula 1 - 2
    NGC 6834 Cygnus Open Cluster 3 - 4
    NGC 6830 Vulpecula Open Cluster 3 - 4
    NGC 6823 Vulpecula Open Cluster 2 - 3
    NGC 6302 Scorpius Planetary Nebular 1 - 2
    NGC 6543 Draco Planetary Nebular 3 - 4
    Double Stars: The Little Gems
    The listing information will be as follows:
    Target Name: Constellation; Folk Name

    Kappa Herculis (k Her) - - - - - Hercules - - Marfik, Marfak, Marsic (The Elbow)
    Alpha Herculis (α Her) - - - - - Hercules - - Rasalgethi (Head of the Kneeler)
    Alpha Scorpii (α Sco) - - - - - Scorpius - - - Antares (The Anti-Mars)
    Beta Scorpii (β Sco) - - - - - Scorpius - - - Acrab
    Beta Cygni (β Cyg) - - - - - Cygnus - - - - - Albireo (The Hen's Beak)
    61 Cygni - - - - - - - - - - - - -Cygnus - - - - - Bessel's Star
    Epsilon Lyrae (ε Lyr) - - - - -Lyra - - - - - The Double Double
    Zeta Ursae Majoris (ζ UMa) - - - - - Ursa Major - - - - Mizor & Alcor
    Alpha Ursae Minoris (α UMi) - - - - - Ursa Major - - - - - Polaris, (The Pole Star)
    Alpha Canis Venaticorum (α CVn) - - - - - Canes Venatici - - - - - - Cor Caroli
    Epsilon Boötis (ε Boo) - - - - - Bootes - - - - - Izar & Pulcherrima (The Veil & The Loveliest)
    Mu Boötis (μ Boo) - - - - - - - - Bootes - - - - -Alkalurops
    Gamma Delphini (γ Del) - - - - - Delphinus - - - - - Job's Coffin
    I hope this helps in some manner of ways :bino2:
  17. Qualia

    Part I: Space

    By Qualia,

    I don't assume that I'm an expert on any of this, so if there are pertinent mistakes in what is written, please correct me. The idea of these posts is simply to give a very rough and very shoddy idea of non-existential Space and Time (for existential notions we've really got to deal with Heidegger, Foucault et al). Hopefully these entries will be short enough to deal with in one sitting but give a general idea of the discourse conducted over the last few centuries. If it isn't working, or you think this kind of thing is redundent, please, let me know.
    Okay...
    Part I
    By the seventeenth century, it was already understood that velocity (the rate of motion in a specific direction: distance divided by time) was a relative concept. From your perspective the hot-air ballon is drifting by, but from the ballon’s perspective, you are going by and both are equally valid points of view. Velocity, then, can only be specified in relation to another object. We all move in relation to other things. It was also understood that velocity, if it is constant, generally goes unfelt but if there’s a sudden change in speed / direction then there is acceleration and acceleration is felt.
    Newton’s Absolutism
    Newton was one of the first to ask himself what are the meanings of these concepts we've just been using such as velocity, motion and what do they refer to?
    To try and answer these questions he came up with a rather profound thought experiment. Imagine there’s a bucket of water and the water is still, and yet as the bucket begins to spin the water’s surface becomes concave and remains so even as the spinning bucket slows and stops. But why is this so? Why does spinning water take this shape?
    That’s easy: because it is spinning, water is somehow pressed against the side of the bucket.
    But what does spinning mean? Spinning with respect to what?
    The bucket? No, because when there is relative motion, the water starts out as flat, becomes concave and when the bucket stops spinning the water continues to spin. So the bucket cannot be the reference for the motion of water.

    The stuff around us, space? Well let’s take the imaginary bucket out to space, what then would serve as the reference, the something with respect to which the water is spinning? Well, for Newton, here lay the answer. If it wasn’t the bucket it had to be Absolute Space. Absolute Space was the reference. When an object is at rest or in motion, accelerating or constant, it is so with reference always to Absolute Space.

    But what is Absolute Space? For Newton it was god-like: eternal, permanent and unchangeable.
    Leibniz’s Relationism
    Newton’s contemporary, Leibniz declared that all this talk of some god-like Absolute Space was nonsense. He asked himself, if Newton is right where is the universe within his Absolute Space and how are we going to know whether that given answer is true or not if we are unable to detect space or changes within it without access to objects? Indeed, how can we say space even exists without implicitly referring to other things?
    Unable to find significant answers to these questions, Leibniz declared that space simply did not exist. Without objects space has no independent meaning or existence. Space is merely a useful language term used to indicate where things are in relative position and movement to each other. Space, in other words, has no meaning beyond providing a semiotic sign for discussing the relationship between things.
    Mach’s Relationism
    Mach raised another interesting question: why in Newton’s theory was velocity relative to another object whereas acceleration was fixed to an unmoving absolute? Might it be that Newton was mistaken and acceleration was also relative?
    Imagine you’re floating in the skies; if you begin to spin the distant earth will no longer appear stationary. You will feel a force on your body and you will witness motion. But if you’re in absolute empty space, Mach argued, and you start spinning you are not going to feel any force on your body and you won’t have any distant object to reference your motion. Thus, how are you able to know whether you are spinning or not?
    It follows that Leibniz was on to something. In absolute empty space there will be no conception of velocity or acceleration because there will be no reference to your motions. In empty space motionlessness and spinning will be indistinguishable. So, if there is no notion of movement in empty space, there cannot be any justification for Newton’s absolute space.
    But we’re still left with a problem: how can we explain the bucket’s water shape if we throw out Absolute Space?
    The solution was that if in empty space there was no concept of spinning or non-spinning, then in our universe, a universe with matter, the force of motion, velocity and acceleration will be relative or proportional to the amount of matter/mass in the universe. The force felt by acceleration, for example, arises simply due to the influence of all the matter in the cosmos. The more matter there is, the more force you will experience.
    Thus, Mach’s universe is the universe of Leibniz. Velocity and acceleration are relative terms and space does not enjoy some independent, god-like existence but is relative only to matter in the universe.
    And here the story will rest until Part II when Einstein will come along and radically transform both the absolutists’ and relationists’ centuries old arguments and critique.
  18. Qualia

    Part II : Space

    By Qualia,

    Following on from Part I: http://stargazerslou...8-qualias-blog/
    Part II – Space
    Introduction
    Before we reach Einstein’s theory of Special Relativity it is necessary to allow Maxwell a voice on our stage, for his own discoveries would play a significant role in Einstein’s own radical insights.
    Maxwell – Setting the Stage
    Building on Faraday’s concept of Field (that which exerts a force beyond its physical presence), Maxwell found that electric and magnetic fields were in fact a single entity and he called this entity the electromagnetic field.
    He discovered that this field travelled at exactly 1,080 million km/h or 671million mph which was also that of the speed of light. Surely, then, he concluded, light must also be part of the electromagnetic field.
    But with this discovery of light's speed, we find ourselves back with the age old problem. As we have seen, velocity only makes sense if it is specified in relation to another object. The only reason I say a car is going 65 mph is because it is relative to me, a stationary person on Earth, for example. However, put that speeding car in a huge plane going at 1,000 mph and I will see the car as moving faster, a whole 1,000 mph faster! This occurs because the speed of the car is added to the plane’s speed. So, if we say light travels at 671 million mph, what is the reference, the benchmark? Light is speeding in relation to what?
    Maxwell had a brain wave. Ocean waves are carried by water. Sound waves are carried by air and we say sound waves travel at 767 mph only because we are referencing them to still air. So, light must also be carried by some kind of substance. Just as I suspect Newton borrowed from Aristotle’s notion of the Prime Mover to give persuasion to his Absolute Space, Maxwell did the same by borrowing from the philosopher the term Aether; the stuff of which Aristotle believed celestial bodies were made. Again, Aether was permanent, omnipresent and unchanging, another god-like figure, and light travelled relative to it.
    Aether?
    If I go for a swim toward a wave, the wave will approach me more quickly than if I am swimming away from it. The same is true for sound waves. So, by the exactly the same reasoning, the quicker I move through Aether, depending on which direction I decide to take, light should travel faster or slower than the stated 671 million mph. The problem was there was no such evidence of this. The famous experiment conducted by Michelson and Morley in 1887 found no such thing. No matter what they did, light continued to travel at its regular 671 million mph.
    A Young Einstein
    Ever since he was a young lad, Einstein had asked himself a rather bizarre question: what would a light wave look like if I could follow it at exactly 671 million mph? According to classical physics and the relativity of velocity, that light wave should appear motionless, so I will be able to reach out and cup for myself a handful of light stuff. However, for one reason and another, Maxwell’s own discoveries prevents light from ever appearing stationary. So why the paradox? What's going wrong?
    It took Einstein about ten years to work out this bewildering question, and at the age of just 26 came forth with the theory of Special Relativity, a theory so startling and radical in its ramifications that it changed the entire course of classical, pre-quantum physics...
    Part III will try to cover some basic aspects.
  19. Qualia
    M 27 - The Dumbbell Nebula
    General Observations
    Messier discovered M 27 in 1764. Some twenty years later, William Herschel recognised its peculiar shape. His son, John, called it the Dumbell and the moniker stuck. In the 19th century, Huggins observed that it wasn't composed of unresolved stars as was originally believed, but through the new science of spectroscopy, realised M 27 was in fact a gigantic cloud composed of luminous gas.
    Along with M 57, the Ring Nebula, M 27 is one of the most observed deep space objects (DSOs) in ameteur astronomy and there is an obvious reason for this: it is a giant of a planetary nebula with a high degree of surface brightness which takes high magnification remarkably well.
    What you are seeing is essentially the remains of a dying supergiant star whose decomposition is creating boundaries of chaos where hot, ionized gas is pushing out onto older, cooler gaseous clumps. M 27's inner section is made up of huge structures of gas and dust somewhere between 20 to 60 million kilometers in size containing the matter of about 3 or 4 times the mass of Earth. These superstructures - for want of a better word - have sufficient density to cast opaque shadows onto the lighter, cooler outer regions giving the nebula that peculiar 'dumbbell' shape.
    The total diameter of M 27 is estimated to be about 6 light years across whose boundary is said to be expanding about 2 to 3 inches every century, whilst its inner region at about 6 to 8 inches. M 27 is between 1,150 to 1,350 light years away with an age of around 9,000 to 10,000 years, making it a relatively young nebula. M 57, for example, is about twice as old.
    City Observations
    The first time I stumbled upon M 27 I had to double check the late night sky to make sure I hadn't found a solitary, wandering cloud; after observing smaller, fainter, nebula structures, I wasn't prepared for the sheer size of the thing. At low magnification it appears as a large, fuzzy cloud-like patch of an indeterminate nature, a blob, so to say, but with the aid of the UHC-S Nebula Filter (Baader), its famous two lobe structure is brought out.
    I have included sketches both without the filter (on the right) and with the filter (on the left) which will hopefully give some idea of what is being viewed. I thought it was also a good idea to include these two sketches for it may help future astronomers decide if the filter is worth its price or not. Note how the nebula is brought-out with the filter, how it takes on a more defined structure but with a notable reduction in star content. It follows that the UHC-S will be pretty redundent when hunting down nebulae.
    The sketches were made using white and grey chalk and brush for the nebula itself, whilst a finely sharpened, white charcoal pencil was used for plotting the stars on the black paper.
  20. Qualia
    M 29 - An Open Cluster
    M 29 is an unassuming, rather lacklustre open cluster made up of about seven bright stars some 3,740 to 7,000 light years away in the constellation of Cygnus and anyone with a 4" telescope or larger may wonder how it was ever included in Messier's list of objects not to be confused with a comet. The answer can be found in Messier's own notes where he writes of the star grouping as "seen...in the form of a nebula", perhaps highlighting just how poor the optics and lenses were in Messier's own time.
    I imagine M 29 would be a rather spectacular cluster if it weren't for a thick cloud of interstellar dust blocking and diminishing the star light by as much as 95%, meaning that many of the stars in the cluster are dimmed by as much as 5 magnitudes. The stars themselves are thought to be young, very hot, and luminous, indicating that the cluster's age is between 4 to 6 million years old. The four or five brightest stars are type B, blue supergiants each with a luminosity of about 160 thousand suns.
    It is estimated that there are over 200 stars in the cluster but on an average seeeing night in the city (mag 3), you should be able to make out about a quarter of this number with ease.
    Observation Notes and Sketch
    The problem with sighting M 29 is twofold:
    i) it is so unassuming, you're not too sure whether you've found a Messier object or just a rather pretty star pattern.
    ii) this area of Cygnus has quite a rich field of stars due to being just outside the Milky Way. Thus it is quite tricky to know where the cluster begins and ends.
    At about 40x the resolution of M 29 into individual stars is easily achieved. The seven of eight brighter stars have a block-box-trapezoibal appearance which does give M 29 a rather austere, mechanical like feel.
    The sketch was made using relatively thick black paper, a white charcoal pencil to mark the stars and then touched up indoors with a tippex pen for the brighter stars. It was scanned into the computer and tidied just a little with the free software Paint.Net.
  21. Qualia
    NGC 6826 - Caldwell 15 - The Blinking Nebula
    General Notes
    Planetary nebulae are the final stage of middle to low mass stars. They are essentially gigantic shells of gas surrounding the nucleus of a dying, progenitor star and one of the best examples of this kind is perhaps NGC 6826.
    On a cosmic scale, planetary nebulae are considered relatively ephemeral phenomena, lasting anything between 30 to 100 thousand years from formation to complete dissipation. It is possible that our own sun will become a planetary nebula after exhausting its own supply of fuel in about 5,000 million years time.
    It is believed that about half the star's mass of NGC 6826 has already been ejected to form the nebula. This disintegration of the dying star causes cosmic wind of newer particles to collide with older material before it forming that hot shell we see from Earth. Planetary nebula have quite a high surface brightness, so are generally easy to find in urban domains and with a small telescope can often be mistaken for an unfocused star.
    NGC 6826 is often referred to as the Blinking Nebula yet the name does not refer to the nebula itself but more to the nature of human vision. Our eyes have their least sensitive light spotting cells in the centre of the fovea. Thus, staring at this object makes it appear to dim or even disappear. If you look away using averted vision, it comes on again and seems brighter. So, playing around with looking-at, looking-away, the nebula appears to blink.
    NGC 6826 is about 2,200 light years away in the Cygnus constellation. It is located south of the spectacular double star 16 Cygni (not included in this sketch). At about 35x it appears like a blurry, unfocused star and at about 50x is easily resolved into a curious cloud-like object.
    Observations from the City & Sketch
    It took a couple of nights to discover the nebula, due in part to a misreading of the star atlas, finding myself lost in a maze of double star systems and relatively bad seeing conditions. I have read that NGC 6828 can sometimes appear with a dim, neon green of grayish-blue hue, but I think one needs larger aperture and darker skies to draw out these features and will be absolutely necessary to spot the nebula's dying central star.
    Once sighted at about 35x, it appears as an unfocused star and with a little more magnification it takes on a cloud like appearance with quite a significant amount of internal brightness. I found it useful to use a low band nebula filter. In my own case an UHC-S but an OIII will also suffice. When trying to identify an object like NGC 6826 in an urban setting, you ought to repeatt observations with and without the filter, increasing magnification as you go. With the filter in place, stars become less apparent but the nebula gains a higher level of contrast enhancement. It was useful to follow through this process right up to about 140x.
    I found that with direct vision the nebula's brightness was clearly reduced and oftentimes would disappear into the darkness. With averted vision it would come alive again, almost as if some playful being was transmitting a slow motion light-code for us to decipher. The Cheeky Winker I noted in my sketch pad, understanding that its message will probably remain a mystery for all time.
    The sketch was conducted without the filter in place. I think the rather pretty double star at the top of the sketch is 61 Cygni.
  22. Qualia
    M 57: The Ring Nebula
    A Little on Lyra
    The constellation Lyra is rather small and faint from the city but it is easy to find due to being home to Vega, the 5th brightest star in the northern hemisphere. Interestingly, around 12,000 years ago, Vega (Alpha Lyrae) served as the Pole star and will again if mankind can survive another 12,000 years.
    Strummed like a guitar rather than plucked like a harp, the lyre is an ancient stringed instrument dating back to around 3,000BCE. According to ancient Greek mythology, Hemes, the son of Zeus, invented the lyre by stealing a sacred cow from his half-brother Apollo and stringing the cow's intestines across a tortoise shell. Evidently, Apollo wasn't too happy with the act but forgave his half-brother in return for the instrument.
    Sometime later, Apollo gave the lyre to Orpheus who became a master of the lyre, enrapturing not only his fellows and the gods of nature but even Hades himself, the dark lord of the underworld. Orpheus met his own violent end when female followers of Dionysus tore him apart limb from limb but in remembrance of this musical genius, Apollo convinced his father Zeus that the instrument played so majestically by Orpheus should become a heavenly constellation and thus, the lyre of Orpheus rests now between Hercules and Cygnus.
    A Little on M 57
    Placed between the exquiste multiple binary star Beta Lyrae (Sheliak - The Tortoise) and Gamma Lyrae (Sulafat - The Shell) is M 57, a small but perfect smoke ring structure. It is about 2,300 light years away from us and was probably created when a red giant ran out of fuel to burn and its shell of gas, which could no longer be gravitationally held to the dying star, was blown away, pushed outward by hot and fast stellar winds from the red giant.
    M 57 is known is a planetary nebula, not because it has anything to do with planets, but because William Herschel, a great astronomer from the late eighteenth century, saw these nebulae, these great spherical clouds round like the planets. M 57's outer layer of gas is about 2 to 3 light years in diameter whilst its darker core is about 1 light year across. It is estimated that this outer ring, that halo we see, expands at about 50 km/s which I imagine from Earth would look like its growing about an inch every century, and all this nebula activity probably began some 10,000 years ago. Today, all that's left of that original red giant is a dense, white dwarf star, the final evolutionary state for a star whose mass was never high enough to become a neutron star.
    Observation Notes

    In my 4" refractor from a city roof top, M 57 looks as if some cosmic wonder has puffed a single smoke ring into the heavens. The halo offers the curious affect of a solid ring of misty light whilst its interior, that central vacuity, black like deep space. Nevertheless, if you remain with M 57 for a while, if you give yourself time, it soon becomes apparent that it is not ring like in shape but oval, tilted from northwest to southeast from its centre and that its central core begins to take on the appearance of feebler, lighter kind of absolute darkness.
  23. Qualia
    M 94 - Spiral Galaxy
    A Bit of General Knowledge
    M 94 is a spiral galaxy some 15 to 17 million light years away from us. It has a diameter of about 56,000 light years and contains some 60,000 million stars. In this sense, M 94 is considered a generally modest galaxy but it does have some rather special qualities. Like M 82, M 94 is a Starburst galaxy, which means it is in the process of creating stars. It appears that high density stellar waves are compressing cosmic matter into protostars at an exceptionally high rate.
    Although face on, the galaxy highlights some kind of spiral structure and is said to resemble an onion, being made up of four complex ring-like regions. The first is a central region of ancient red stars estimated to be around 10,000 million years old. The second area is a starburst region giving itself over to star formation. This is followed by another ring-like area made up of more ancient red stars and another starburst region. Finally, there's been observed a very faint outer ring. In this sense, M 94 is a rather rare galaxy whereby two interstellar cosmic waves are creating stars simultaneously in two very distinct regions.
    Observation from the City
    M 94 has a special place in my records for it was the first galaxy observed with the Tal 100rs. With the scope on that particular Spring evening in the city, M 94 appeared at first like a bright, luminous planetary nebula, but resting with her for a little while revealed a brighter core surrounded by a nebulous like halo. A rather pretty sight, especially as framed by the surrounding stars and with the use of a Telrad and decent scope finder, shouldn't cause much problem to find in an urban setting.
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